hUCMSCs对D-半乳糖致衰老小鼠心脏保护作用

CARDIOPROTECTIVE EFFECT OF HUMAN UMBILICAL CORD MESENCHYMAL STEM CELLS IN D-GALACTOSE-INDUCED AGING MICE

目的探讨人脐带间充质干细胞(hUCMSCs)对D-半乳糖(D-gal)诱导的衰老小鼠的心脏保护作用及其可能的机制。方法将24只8周龄雄性C57BL/6小鼠随机分为对照组、模型组和干细胞组,每组8只。对照组颈背部皮下注射灭菌注射用水(5mL·kg^(-1)·d^(-1))8周,模型组和干细胞组颈背部皮下注射D-gal(150 mg·kg^(-1)·d^(-1))8周,至D-gal注射第5周和第7周时,干细胞组分别尾静脉注射1×106个hUCMSCs,对照组和模型组尾静脉注射1×PBS(每只0.2mL)。采用苏木精-伊红染色观察心肌组织病理改变,Western Blot检测热休克蛋白70(HSP70)和血管内皮生长因子(VEGF)蛋白表达水平,RT-PCR检测炎症小体相关基因NOD样受体蛋白3(NLRP3)、白细胞介素18(IL-18)、白细胞介素1β(IL-1β)mRNA的表达。结果病理学检查显示,模型组出现心肌组织退行性改变,而对照组和干细胞组无相应改变。模型组心肌组织HSP70和VEGF蛋白表达较对照组显著下降,干细胞组HSP70和VEGF蛋白表达较模型组显著升高(F=9.76、43.87,P<0.05)。模型组心肌组织中炎症小体相关基因NLRP3、IL-18、IL-1βmRNA表达较对照组显著增加,干细胞组心肌组织中炎症小体相关基因表达较模型组显著下降(F=30.04~44.45,P<0.05)。结论 hUCMSCs能有效缓解D-gal诱导的心脏老化,其机制可能与促进血管新生和抑制NLRP3炎症小体通路有关。

Objective To investigate the cardioprotective effect of human umbilical cord mesenchymal stem cells（hUCMSCs）in D-galactose（D-gal）-induced aging mice and its potential mechanism. Methods Twenty-four eight-week-old C57BL/6 male mice were randomly and equally divided into control group,model group,and stem cell group.The control group received subcutaneous injection of sterile water（5 mL·kg^-1·d^-1）on the back of the neck for eight weeks.The model group and stem cell group received subcutaneous injection of D-gal（150 mg·kg^-1·d^-1）on the back of the neck for eight weeks.At weeks 5 and 7,the stem cell group received tail vein injection of 1×10^6 hUCMSCs,while the control group and model group received tail vein injection of 1×PBS（0.2 mL for each mouse）.The pathological changes in myocardium were evaluated by HE staining.The protein expression levels of heat shock protein 70（HSP70）and vascular endothelial growth factor（VEGF）were determined by Western Blot.RT-PCR was used to determine the mRNA expression of inflammasome-related genes,the NOD-like receptor family,pyrin domain-containing protein 3（NLRP3）,interleukin-18（IL-18）,and interleukin-1β（IL-1β）. Results Pathological examination showed that myocardial tissue degeneration occurred in the model group rather than the control group or the stem cell group.The model group had significantly lower protein expression levels of HSP70 and VEGF in the myocardium than the control group,while the stem cell group had significantly higher protein expression levels of HSP70 and VEGF in the myocardium than the model group（F=9.76 and 43.87,P〈0.05）.The model group had significantly higher mRNA expression of NLRP3,IL-18,and IL-1β than the control group,while the stem cell group had significantly lower mRNA expression of those genes than the model group（F=30.04-44.45,P〈0.05）. Conclusion hUCMSCs can effectively delay D-gal-induced cardiac aging,possibly by promoting neovascularization and inhibiting the NLRP3 inflammasome signaling pathway.